將文本文件的大小放入緩沖區時出錯

Question

if (fwarrior != NULL) {
/* Go to the end of the file. */

 if (fseek(fwarrior, 0, SEEK_END) == 0) {
 /* Get the size of the file. */
 long bufsize = ftell(fwarrior);
 if (bufsize == -1) 
 {
     printf("Error in reading the size of file"); 
 }

 /* Allocate our buffer to that size. */
 buffer = malloc(sizeof(char) * (bufsize + 1));

 /* Go back to the start of the file. */
 if (fseek(fwarrior, 0, SEEK_SET) == 0) 
 { 
     printf("Error = File is considered NULL"); 
 }

 /* Read the entire file into memory. */
 size_t newLen = fread(buffer, sizeof(char), bufsize, fwarrior);

 if (newLen == 0) 
 {
      fputs("Error reading file", stderr);
 } 

 else 
 {
      buffer[newLen] = '\0'; /* Just to be safe. */
 }

 }  
 }

在Windows上通過VS2012運行此代碼時，出現的是"Error = File is considered NULL"

我試圖將某個文件的內容分配到緩沖區中，並在以后使用sscanf創建一個單鏈表，以將文件的內容分配到它們各自的變量中。

我剛從一個網站上獲得了上面的代碼，該代碼的制造商表示，上面的代碼基本上是讀取文件的全部內容，然后將它們分配到緩沖區中，以便以后可以使用sscanf 。

樣品：

#include <stdio.h>
#include <stdlib.h>
typedef struct hero_data{
    char name[254];
    char title[254];
    int encoding;
    int startstr;
    double incstr;
    int startdex;
    double incdex;
    int startintel;
    double incintel;
    int basemindmg,basemaxdmg;
    double bat;
    double basearmor;
    struct hero_data *next;
    struct hero_data *type;
    struct hero_data *Class;
}hero;
int main()
{
hero *curr[] = {0};
hero *head;
hero *tail;
int totalwarrior = 0;
FILE *fwarrior;
char filename[256];
char *buffer = NULL;
size_t newLen;
printf("Name of Roster File for Warriors?(without .extension): \n");
scanf("%s",&filename);
strcat(filename,".txt");
fwarrior = fopen(filename,"r");

if (fwarrior != NULL) {
    /* Go to the end of the file. */
    if (fseek(fwarrior, 0, SEEK_END) == 0) {
        /* Get the size of the file. */
        long bufsize = ftell(fwarrior);
        if (bufsize == -1) 
        {
            printf("Error in reading the size of file"); 

        }

    /* Allocate our buffer to that size. */
    buffer = malloc(sizeof(char) * (bufsize + 1));

    /* Go back to the start of the file. */
    if (fseek(fwarrior, 0, SEEK_SET) == 0) //So is this the right way to use fseek?
    { 

    /* Read the entire file into memory. */
    size_t newLen = fread(buffer, sizeof(char), bufsize, fwarrior);

    if (newLen == 0) 
    {
        fputs("Error reading file", stderr);
    } 
    else 
    {
        buffer[newLen] = '\0'; /* Just to be safe. */
    }
}
}   

while(fgets(buffer, sizeof buffer, fwarrior) != NULL)
{
if(13 == sscanf(buffer,"%s[^,] , %s[^,] , %d , %d , %lf , %d , %lf , %d , %lf , %d , %d , %lf , %lf", &curr[totalwarrior]->name,&curr[totalwarrior]->title,&curr[totalwarrior]->encoding,&curr[totalwarrior]->startstr,&curr[totalwarrior]->incstr,&curr[totalwarrior]->startdex,&curr[totalwarrior]->incdex,&curr[totalwarrior]->startintel,&curr[totalwarrior]->incintel,&curr[totalwarrior]->basemindmg,&curr[totalwarrior]->basemaxdmg,&curr[totalwarrior]->bat,&curr[totalwarrior]->basearmor))
{
    if (head == NULL)
    {
        head = curr[totalwarrior];      
    }
    else 
    {
        tail->next=curr[totalwarrior];
    }
    tail = curr[totalwarrior];

    if (head!=NULL)
    {
        curr[totalwarrior] = head;
        do {
        printf("%s\n%s\n%d\n%d\n%.1lf\n%d\n%.1lf\n%d\n%.1lf\n%d\n%d\n%.1lf\n%.1lf\n\n",curr[totalwarrior]->name,curr[totalwarrior]->title,curr[totalwarrior]->encoding,curr[totalwarrior]->startstr,curr[totalwarrior]->incstr,curr[totalwarrior]->startdex,curr[totalwarrior]->incdex,curr[totalwarrior]->startintel,curr[totalwarrior]->incintel,curr[totalwarrior]->basemindmg,curr[totalwarrior]->basemaxdmg,curr[totalwarrior]->bat,curr[totalwarrior]->basearmor);
        curr[totalwarrior] = curr[totalwarrior]->next = curr[totalwarrior+1];
        curr[totalwarrior] = NULL; 
        printf("Before Total %d\n",totalwarrior);
        totalwarrior++;
        printf("Now Total %d\n",totalwarrior);
        }while(curr[totalwarrior-1] != NULL);
    } free(curr[totalwarrior]);
}
}
}
}
//I created a typedef struct named curr that is in the form of array. It is legit.
//I do not know the limit of the file so that's why I am trying to use the function above to get the size of the file in order to use `sscanf`.

//I made the code `13 == sscanf(...)` because within the file, there will be multiple "sets" of data that are in the set of 13 variables. Everytime when the program reads the 13th variable, I will add counter to `[totalwarrior]` of the typedef struct named `curr`.

這是程序將讀取的示例文件：

Relay Chestdrop
Snow Damsel
230
16
1.7
16
1.6
21
2.9
38
44
1.7
1.24
Linnea Reversa
Vanquisher
214
18
1.5
16
1.5
27
3.2
40
58
1.7
1.24
Kyle
Hoarder
255
19
1.7
20
1.9
22
2.5
35
41
1.7
1.8
Leo
Wiccan Monster
236
16
1.7
15
1.5
22
3
42
48
1.7
1.1
Changer
Changer
191
19
2
24
3
17
1.5
37
46
1.6
1.36
Consortio Piercoptic
Elvish Sharpshooter
177
16
1.7
21
2.9
15
2.6
36
42
1.7
1.94
Tinklez
Osteoarcher
149
15
1.6
22
3
16
1.55
37
43
1.7
2.08
Weeeeheeee-urrr
Silhouette Devil
180
15
2
20
2.9
18
2
35
41
1.7
1.8
Deckard Haemofoot
Bovine Captain
71
24
2.3
14
1.5
23
1.6
47
57
1.7
2.96
Shelgar
Blessed Hero
92
21
2.4
20
2.4
18
1.5
42
51
1.6
1.8
Tomahawk
Genghis Tycoon
120
25
2.5
20
2.2
18
1.6
49
53
1.7
1.8
Beelzebub
Ruinbearer
108
26
3.2
11
0.9
13
2.1
53
69
1.7
0.54

Answer 1

fseek運行正常，但是您誤解了結果。

返回值

如果成功，函數將返回零。 否則，它將返回非零值。 如果發生讀取或寫入錯誤，則會設置錯誤指示器（錯誤）。

（來自CPP參考 ）